1. Field of the Invention
The present invention relates to a side by side type refrigerator and a method for controlling a temperature in a vegetable box therein, and more particularly, to a side by side type refrigerator which can cool down a vegetable box to a preset temperature without separate cooling duct, and a method for controlling a temperature in a vegetable box therein.
2. Background of the Related Art
Refrigerators may be sorted as a conventional refrigerator which has a freezing chamber and a refrigerating chamber arranged in a vertical direction, and a side by side type refrigerator which has the freezing chamber and the refrigerating chamber arranged side by side. FIG. 1 illustrates a front view of a related art side by side type refrigerator with doors opened, and FIG. 2 illustrates a section of refrigerating chamber in the related art side by side type refrigerator, referring to which a structure of the related art side by side type refrigerator will be explained.
The side by side type refrigerator is provided with a barrier 30 stuffed with an insulating material for separating the freezing chamber 10 and the refrigerating chamber 20 in left and right sides. There is an evaporator 12 in rear of the freezing chamber 10 for cooling down air in the refrigerator, and there is a fan 14 over the evaporator for circulation of cooled air within the refrigerator. And, there is a damper assembly 24 having a damper 22 over the refrigerating chamber, and there is a vegetable box 28 under the refrigerating chamber for storage of vegetable and the like. There is a cold air passage 16 in an upper portion of the barrier 30 for supplying a cold air heat exchange in the evaporator 12 to the refrigerating chamber 10, and there is a return passage 18 in a lower portion of the barrier 30 for return of a cold air having circulated through the refrigerating chamber 20 and heated up to a relatively high temperature toward the evaporator 12, again. There is the damper 22 at an outlet of the cold air passage 16 for regulating cold air supply to the refrigerating chamber 20, to an outlet of which damper 22 a cold air discharge opening 25 for supplying the cold air to the refrigerating chamber 18 and a cold air duct 26 for supplying the cold air to the vegetable box 28 are connected. The unexplained numeral 29 denotes a temperature sensor for sensing a temperature in the refrigerating chamber 20.
A process for circulating cold air through a related art side by side type refrigerator will be explained with reference to FIGS. 1 and 2.
One portion of the cold air, heat exchanged in the evaporator 12 through which cold refrigerant circulates, is supplied to the freezing chamber 10 by the fan 14, and the other portion of the cold air is supplied toward the damper 22 in the refrigerating chamber 20 through the cold air passage 16. A portion of the cold air supplied toward the damper 22 in the refrigerating chamber 20 is discharged to the refrigerating chamber 20 through the cold air discharge opening 25, and, therefrom, flows down to a lower portion of the refrigerating chamber 20. And, the other portion of the cold air supplied toward the damper 22 is provided to the vegetable box 28 in a lower portion of the refrigerating chamber 20 through a cold air duct 26 for the vegetable box in a rear wall of the refrigerating chamber 20. The cold air supplied to the freezing chamber 10 and the refrigerating chamber 20 is heated to a relatively high temperature through heat exchange with the stored food, and the like. The cold air heated to a relatively high temperature in the refrigerating chamber 20 flows toward the evaporator 12 again through the return air passage 18 formed in a lower portion of the barrier 30. The cold air circulation in the refrigerator repeats the aforementioned process. Cold air circulation in a conventional refrigerator is almost same with the aforementioned cold air circulation in the side by side type refrigerator, except that positions of the cold air passages and the damper are different.
A method for controlling a temperature in the related art side by side type refrigerator will be explained with reference to FIGS. 1 and 3.
In order to determine the refrigerator of putting into operation, a freezing chamber temperature Tf, or a refrigerating chamber temperature Tc is compared to a preset temperature Ts (S10). If it is found as a result of the comparison that the freezing chamber temperature Tf, or the refrigerating chamber temperature Tc is higher than the preset temperature Ts, the refrigerator is put into operation for supplying cold air to the freezing chamber 10 and the refrigerating chamber 20 (S11). That is, the compressor (not shown) and the fan 14 are driven, to supply cold refrigerant to the evaporator 12, to cool down air around the evaporator 12 by heat exchange with the evaporator. The cold air is supplied to the freezing chamber 10 and the refrigerating chamber 20. In this instance, the damper 22 is left open for supplying the cold air to the refrigerating chamber 20 (S12). Provided the damper 22 is opened, a portion of the cold air is supplied to inside of the refrigerating chamber 20, and the other portion of the cold air is supplied to the vegetable box 28 through the cold air duct 26. In the meantime, as the temperature in the refrigerating chamber 20 will drop as the cold air supply to the refrigerating chamber 20 is kept on, it is required to prevent the refrigerating chamber from being subcooled. Therefore, the temperature sensor 29 in the refrigerating chamber senses the refrigerating chamber temperature and compares to the preset refrigerating chamber temperature Tcs (S13). If it is found as a result of the comparison that the refrigerating chamber temperature Tc is lower than the preset refrigerating chamber temperature Tcs, the damper 22 is closed to stop cold air supply to the refrigerating chamber (S14) as there is a possibility of subcooling of the refrigerating chamber, otherwise the damper 22 is left open. In order to prevent unnecessary operation of the refrigerator, the temperature sensor(not shown) in the freezing chamber 50 senses the freezing chamber temperature Tf, and compares to a preset freezing chamber temperature Tfs (S15). If it is found as a result of the comparison that the freezing chamber temperature Tf is lower than the preset freezing chamber temperature Tfs, the operation of the refrigerator is stopped, otherwise the operation of the refrigerator is kept on. (S16). The aforementioned control method is in general programmed in a microcomputer, so that the microcomputer controls the compressor, the fan, the damper, and the like, to keep the freezing chamber temperature at approx. -18.degree. C., the refrigerating chamber temperature at approx. 3-4.degree. C., and the vegetable box temperature at approx. 5.degree. C.
However, the related art method for controlling a temperature in a side by side type refrigerator has the following problems.
First, the related art side by side refrigerator shows a case when the vegetable box is subcooled or cooled inadequately because, as has been explained, the damper 22 is closed even if the vegetable box 28 is not cooled down adequately if the refrigerating chamber temperature Tc is lower than the preset refrigerating chamber temperature Tcs, that causes the inadequate cooling. And, if the operation of the refrigerator is stopped and the damper in the refrigerating chamber 20 is closed as the freezing chamber temperature or the refrigerating chamber temperature meets the preset temperature, the cold air in the refrigerating chamber 10 naturally circulates to flow down to a lower portion of the refrigerating chamber, which causes subcooling of the vegetable box 28 provided in a lower portion of the refrigerating chamber 20. And, in the case of the side by side type refrigerator, the damper 22 in the refrigerating chamber is positioned at an upper most portion of the refrigerating chamber 20, from which the cold air duct 26 is lead to the vegetable box 28. Therefore, the cold air duct 26 is longer than the cold air duct in the conventional refrigerator, with a greater flow resistance, which causes the cold air flowing through the cold air duct 26 to be heated as the cold air flows. At the end, the heated cold air to the vegetable box 28 can not cool down the vegetable box 28, adequately.
Second, the related art structure causes deterioration of an insulating performance of the refrigerator and a production cost rise, because the cold air duct 26 to the vegetable box 28 is provided separately. Moreover, foaming into a space between an inner case and an outer case of the refrigerating chamber having the cold air duct 26 formed therein is required in view of a refrigerator fabrication process, that deteriorates a working efficiency on a production line and causes the cold air duct 26 to impede a smooth flow of the foam liquid to deteriorate the foaming. The formation of the cold air duct 26 in a rear wall of the refrigerating chamber reduces a thickness of the insulating layer in the rear wall of the refrigerating chamber.